JPH063998U - Boom work vehicle safety device - Google Patents

Abstract

(57) [Summary] [Purpose] To provide a safety device for a boom work vehicle that can maintain the stability of the vehicle body without forcibly stopping the fall operation of the boom. [Construction] The safety device 20 includes a hoisting and lowering detecting means 21 for detecting a hoisting and lowering angle of a boom, a length detecting means 22 for detecting a length of the boom, and a maximum for keeping the vehicle body stable for each hoisting and lowering angle of the boom. Storage means 23 that stores the boom length in advance
With. Furthermore, when the length of the boom detected by the length detection means 22 is longer than the maximum boom length stored in the storage means 23, which corresponds to the hoisting angle of the boom detected by the hoisting detection means 21. In addition, automatic reduction control means 24 for reducing the boom so that the length of the boom is less than or equal to the maximum boom length is also provided.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a safety device for a boom work vehicle such as an aerial work vehicle having a boom that can be undulated and retracted.

[0002]

[Prior art]

 A boom that can be lifted and retracted is installed on the body of an aerial work vehicle, and a workbench is installed at the tip of the boom. A workbench can be boarded by an operator who can be moved to any height through each actuation of the boom. However, a moment acts on the boom in the direction of tipping the vehicle (hereinafter referred to as the tipping moment). This overturning moment increases as the boom is lengthened or the boom is laid down and moved closer to a horizontal position. There is a risk of falling into a different state. For this reason, conventional aerial work vehicles are equipped with a safety device that prohibits the boom from extending or falling when the actual overturning moment exceeds the maximum allowable moment. It was being done.

However, when the safety device for controlling the operation of the boom is used in this way, for example, even when the boom is being tilted, the tilting operation may be suddenly stopped. Will occur. Then, when such a situation occurs, an operator unfamiliar with the aerial work vehicle does not know why the operation of the boom has stopped, and confuses that the boom or the like may have failed. There is a risk that

Therefore, for example, a safety device as disclosed in Japanese Patent Publication No. 4-19159 is considered. This safety device calculates the boom attitude based on the hoisting angle and extension of the boom that is tilted, and when the calculated boom attitude exceeds the attitude range (allowable attitude range) that produces the maximum allowable moment. In addition, by automatically reducing the boom, the posture of the boom is kept within the allowable posture range, and the fall operation of the boom is continued.

[0005]

[Problems to be solved by the device]

 However, in the illustrated safety device, the boom posture is recalculated each time the boom falls, and the automatic boom reduction control is not executed during the calculation. For this reason, the boom is intermittently contracted, which causes a problem that the rider on the workbench feels uncomfortable (it feels like moving in a zigzag manner). In addition, the computing unit that computes the attitude of the boom is often expensive, and there is also the problem that this leads to a cost increase of the safety device.

The present invention has been made in view of the above problems, can be manufactured at low cost, and allows the boom to perform smooth automatic reduction control when the attitude of the boom exceeds the allowable range. However, it is an object of the present invention to provide a safety device for a boom work vehicle that allows the boom to continue the fall operation.

[0007]

[Means for Solving the Problems]

 In order to achieve the above-mentioned object, the safety device of the present invention is provided with a hoisting detection means for detecting a hoisting angle of a boom, a length detecting means for detecting a boom length, and a vehicle body for each hoisting angle of the boom. And a storage means for storing in advance the maximum boom length that keeps stable. Further, when the length of the boom detected by the length detection means is longer than the maximum boom length stored in the storage means that corresponds to the hoisting angle of the boom detected by the hoisting detection means, It also has automatic reduction control means for reducing the boom so that the length of the boom is less than the maximum boom length.

[0008]

[Action]

 In such a safety device, when the hoisting / lowering angle of the boom is detected by the hoisting / lowering detection means, the maximum boom length corresponding to the detected hoisting angle is immediately detected from the information on the maximum boom length stored in the storage means. It is selected and compared with the boom length detected by the length detection means. When it is determined that the detected boom length exceeds the maximum boom length, the automatic reduction control means automatically reduces the boom until the boom length becomes equal to or less than the maximum boom length. By thus selecting the necessary information from the storage means, it is possible to improve the operation responsiveness of the automatic reduction control means for detecting the boom hoisting angle, for example, while the boom hoisting operation is in progress. , The boom can be automatically reduced smoothly.

[0009]

【Example】

 Hereinafter, preferred embodiments of the present invention will be described with reference to the drawings. First, FIG. 1 shows an aerial work vehicle 10 equipped with a safety device according to the present invention. At the rear of the vehicle body 11 of the aerial work vehicle 10, a swivel base 12 is attached which is horizontally rotatable with respect to the vehicle body 11. A boom 13 is telescopically attached to the upper part of the swivel base 12 so as to be telescopic. The hoisting operation of the boom 13 is performed by the telescopic operation of the hydraulic hoisting cylinder 15 mounted between the swivel base 12 and the boom 13. Further, the extension / contraction operation of the boom 13 is performed by the extension / contraction operation of the hydraulic extension / contraction cylinder 16 incorporated in the boom 13.

A workbench 17 is horizontally attached to the tip of the boom 13, and an operator on the workbench 17 operates the operation device 18 provided on the workbench 17 to operate the boom. It is possible to control the operation of the turntable 13 and the swivel base 12 and move to any height.

However, the boom 13 is subject to a falling direction moment generated by its own weight, the weight of the workbench 17 mounted, and the like. In order to prevent the tipping direction moment from exceeding the moment value (hereinafter referred to as the maximum moment) that can be supported by the jacks 19 attached to the front, rear, left, and right of the vehicle body 11, the present invention is applied to the aerial work vehicle 10. The safety device concerning is attached. The safety device will be described below with reference to FIG.

The safety device 20 includes an undulation angle detector 21, a length detector 22, a storage unit 23, and an automatic reduction control unit 24. As shown in FIG. 1, the undulation angle detector 21 is attached to the side surface of the base end portion of the boom 13, and detects the undulation angle of the boom 13 with respect to the horizontal direction and outputs a detection signal. The length detector 22 is attached to the tip of the boom 13 and detects the length of the boom 13 (boom length) and outputs a detection signal. In the storage unit 23, a boom length (hereinafter, referred to as a maximum allowable boom length) that can generate the maximum moment for each hoisting angle of the boom 13 is stored and set in advance.

The automatic reduction control unit 24 is composed of a comparator 25 and a reduction command device 26. The comparator 25 reads the maximum allowable boom length corresponding to the actual hoisting angle of the boom 13 detected by the hoisting angle detector 21 from the storage unit 23. Then, the maximum allowable boom length and the actual boom length of the boom 13 detected by the length detector 22 are compared and determined. If it is determined that the actual boom length is equal to or less than the maximum allowable boom length, no signal will be output. However, when it is determined that the actual boom length exceeds the maximum allowable boom length, a determination signal is sent to the reduction command device 26.

Upon receiving the determination signal sent from the comparator 25, the reduction command device 26 sends a reduction command signal to the hydraulic pressure supply control device 31. The hydraulic pressure supply control device 31 normally controls the supply of hydraulic oil discharged from the hydraulic pump 32 to the undulating cylinder 15 and the telescopic cylinder 16 according to the operation of the operating device 18. Then, the hydraulic pressure supply control device 31 that receives the reduction command signal supplies the hydraulic oil to the telescopic cylinder 15 even when the operating device 18 is not performing the reduction operation, and causes the telescopic cylinder 15 to perform the contraction operation.

According to the safety device 20 configured as described above, for example, as shown in FIG. 3, while the boom 13 is extended to the fully extended state, the operating device 18 performs the laying-down operation to move the pedestal from the standing state. When operated, when the comparator 25 determines that the actual boom length exceeds the maximum allowable boom length at a certain undulation angle, the boom 13 automatically moves to the maximum allowable boom length. Reduction operation is performed until it becomes L or less. Therefore, the stability of the vehicle body 11 is not impaired, and the boom 13 can continue the fall operation in response to the fall operation. Then, as the boom 13 falls, the maximum allowable boom lengths (L ′, L ″, ...) Shorter in sequence are selected and set in the comparator 25, and the retracting operation of the boom 13 continuously follows it. To be done.

In this way, the maximum allowable boom length stored in advance in the storage unit 23 is selected and set according to the change in the hoisting angle of the boom 13, so that, for example, the hoisting angle and extension amount of the boom can be set. After the detection, the posture of the boom 13 is calculated once, and the automatic reduction control of the boom 13 can be executed in a shorter time than that in which the calculation result is compared with the previously stored regulation posture. Therefore, the worker who has boarded the workbench 16 can smoothly descend without feeling uncomfortable. Moreover, since the memory components used in the storage device 23 are generally inexpensive, it is possible to manufacture the safety device 20 at a lower cost than when using a computing device for computing the boom posture.

If the jack (see 19 in FIG. 1) that supports the vehicle body is an aerial work vehicle that overhangs laterally of the vehicle body, the maximum allowable boom length also depends on the amount of overhang of the jack. Since the maximum allowable boom length is longer as the protruding amount is different, the maximum allowable boom length selected by the comparator (see 24 in FIG. 2) may be changed according to the protruding amount.

[0018]

[Effect of device]

 As described above, in the safety device of the present invention, the maximum boom length is stored in advance for each boom hoisting angle, the maximum boom length corresponding to the detected boom hoisting angle is immediately selected, and the maximum boom length is selected. The boom is automatically retracted so that the length is less than the length. Therefore, for example, even when the boom is tilted and the boom undulation angle changes every second, the boom automatic reduction control can be executed without delaying the change of the undulation angle. The tip of the can be lowered smoothly. In addition, since the memory for storing the maximum boom length data is often inexpensive, the safety device itself should be manufactured at a lower cost than when using a computing unit that performs complicated computation as in the past. You can

[Brief description of drawings]

FIG. 1 is a perspective view of an aerial work vehicle equipped with a safety device according to the present invention.

FIG. 2 is a configuration diagram of the safety device.

FIG. 3 is an operation explanatory view of the safety device.

[Explanation of symbols]

 13 boom 16 telescopic cylinder 20 safety device 21 undulation angle detector 22 length detector 23 memory device 24 automatic reduction control unit

Claims (1)

[Scope of utility model registration request] 1. A safety device for a boom working vehicle, comprising a boom capable of undulating / extending and contracting on a vehicle body, comprising undulation detection means for detecting an undulation angle of the boom, and a length for detecting a length of the boom. And a storage unit that stores in advance a maximum boom length for which the vehicle body is stably maintained for each boom hoisting angle, and the length of the boom detected by the length detection unit. Is longer than the maximum boom length stored in the storage means that corresponds to the hoisting angle of the boom detected by the hoisting detection means, the length of the boom is the maximum boom length. A boom work vehicle safety device comprising: automatic reduction control means for reducing the boom as described below.